Work cycle determination system for a pump

ABSTRACT

A work cycle determination system for a fracking pump is provided. The work cycle determination system includes a pressure sensor adapted to generate a signal indicative of a pressure generated by the fracking pump, and a controller communicably coupled to the pressure sensor. The controller receives the signal indicative of the pressure generated by the fracking pump over a predefined period of time. The controller identifies a boundary of a work cycle within the predefined period of time by analyzing the signal. The controller also determines a peak pressure of the work cycle and a time duration of the work cycle. The controller further determines a type of the work cycle of the fracking pump based on the peak pressure and the time duration of the work cycle.

TECHNICAL FIELD

The present disclosure relates to a work cycle determination system fora pump. More particularly, the present disclosure relates to the workcycle determination system for a fracking pump used in oil and gasindustry.

BACKGROUND

Generally, fracking pumps are employed during downhole activities in oiland gas industry. Such activities may include perforation and frackingfor production of oil and/or gas from rock formations. In somesituations, multiple fracking pumps may be used in tandem to performperforation and fracking in a. cyclic manner or as per operationalrequirements. Further, multiple fracking pumps may be grouped togetherto improve fluid flow and fluid pressure. In such a situation, differentgroups of the fracking pumps may be assigned preset activities, such aseither perforation or fracking, to be performed sequentially or as peroperational requirements.

The fracking pump includes an intake manifold at low pressure and adischarge manifold at high pressure. The high discharge pressure, inturn may induce excessive stress on components of the fracking pump,such as one or more valves, seals, bearings, and so on. Furthermore,different activities may induce varying levels of stress on thecomponents of the fracking pump, in turn limiting use of the frackingpump for different activities. For example, higher stress activities maylimit an operation of the fracking pump for a limited number of hoursbefore the fracking pump may be operated again for the same or adifferent activity. Also, higher stress activities may require frequentservicing of the fracking pump in order to identify worn out componentsand limit breakdown of the fracking pump during an ongoing activity.Moreover, the fluid pumped by the fracking pump may be gritty andcorrosive leading to early failure of the fracking pump. The failure ofthe fracking pump may result in downtimes amounting to loss of time andmoney to the site operator.

U.S. Pat. No. 5,353,637 describes a modular sonde for obtaining variousmeasurements in open or cased boreholes. The sonde is conveyed on anelectric wire line with or without a coiled tubing for conveyinghydraulic energy from a surface. Modules common to the configurationsinclude telemetry electronics, orientation, hydraulic energyaccumulator, fluid chambers, hydraulic power, pump out, and flowcontrol. Each configuration has a stress/rheology module suited to theborehole situation. An open-hole sonde configuration has astress/rheology module with an instrumented, inflatable packer module,an orienting module, and a probe module. A second open-hole sondeconfiguration has a stress/rheology module with an instrumented straddlepacker assembly. A cased-hole sonde configuration has a gun blockassembly, a gun block orienting module hydraulics for formation pre-testand hydraulics for stressing the formation to obtain data related toformation stress characteristics. A second cased-hole sondeconfiguration has a straddle-packer assembly, a casing perforationdevice in the straddle interval, and hydraulics for stressing theformation to obtain data related to formation stress characteristics.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a work cycle determinationsystem for a fracking pump is provided. The work cycle determinationsystem includes a pressure sensor associated with the fracking pump. Thepressure sensor is adapted to generate a signal indicative of a pressuregenerated by the fracking pump. The work cycle determination systemincludes a controller communicably coupled to the pressure sensor. Thecontroller receives the signal indicative of the pressure generated bythe fracking pump over a predefined period of time. The controlleridentifies a boundary of a work cycle within the predefined period oftime by analyzing the signal. The controller also determines a peakpressure of the work cycle and a time duration of the work cycle. Thecontroller further determines a type of the work cycle of the frackingpump based on the peak pressure and the time duration of the work cycle.

Other features and aspects of this disclosure will be apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a work cycle determinationsystem, according to one embodiment of the present disclosure;

FIG. 2 is a graphical representation of pressure generated by a frackingpump with respect to time, according to one embodiment of the presentdisclosure; and

FIG. 3 is a flowchart of working of the work cycle determination systemof FIG. 1, according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or the like parts. Referring to FIG.1, a schematic representation of a work cycle determination system 10for a fracking pump 12 is illustrated. The fracking pump 12 may be anypump known in the art, such as a positive displacement pump. Thefracking pump 12 is associated with oil and gas industry and employed ata site (not shown) during a fracking process. The fracking processrefers to a process of drilling down into the earth and directing highpressure fluid at a rock formation (not shown) to release trapped oiland/or gas which may be pumped to the ground level. In variousembodiments, one or more fracking pumps may be combined to improve fluidflow and fluid pressure. The fracking process may also be referred to asa hydro-fracturing process, micro-hydraulic fracturing process or ahydro-fracking process.

The fracking pump 12 provides flow of one or more fluids at a highpressure for the fracking process, The fluid may include, but notlimited to, water, sand, chemicals, and so on, or a combination thereof.During the fracking process, the fluid is pressurized by the frackingpump 12 and injected through a well (not shown) into the rock formationat high pressure.

The high pressure of the fluid forces oil and/or gas trapped within therock formation to flow out to a head (not shown) of the well. Thefracking process may be carried out by drilling vertically orhorizontally to the rock formation based on application requirements.The fracking process creates new pathways for release of the oil and/orgas therein or may be used to extend existing channels. Morespecifically, the fracking process refers to fracturing of the rockformation using high pressure fluid in order to release the oil and/orgas trapped therein.

The fracking pump 12 may operate in various types of work cycles,namely, a system test cycle, a fracking cycle, and a perforation cycle.If the fracking pump 12 is not working, the fracking pump 12 is referredto as in an idle work cycle. Each type of the work cycle has one or morecharacteristics such as a peak pressure, an average pressure, a timeduration, and the like that may be different from the other types of thework cycles.

The work cycle determination system 10 includes a pressure sensor 14associated with the fracking pump 12. The pressure sensor 14 may be anypressure sensor known in the art, such as a piezo-resistive typepressure sensor, a piezo-electric type pressure sensor, a capacitivetype pressure sensor, an electromagnetic type pressure sensor, anoptical type pressure sensor, a potentiometric type pressure sensor, andso on.

The pressure sensor 14 is adapted to generate a signal indicative of adischarge pressure of the fracking pump 12. In one embodiment, thepressure sensor 14 may be coupled to any portion of the fracking pump12, such as outlet discharge manifold (not shown) thereof. In anotherembodiment, the pressure sensor 14 may be coupled to any portion of thewell, such as the head of the well, within the well as a downholedevice, and so on. The pressure sensor 14 may be further adapted tocapture the signal at a high frequency.

The work cycle determination system 10 also includes a controller 16communicably coupled to the pressure sensor 14. Accordingly, thecontroller controller 16 is adapted to receive the signal indicative ofthe pressure generated by the fracking pump 12 and to identify aboundary of a work cycle of the fracking pump 12. The controller 16 maystore the pressure signals received from the pressure sensor 14. Morespecifically, in the illustrated embodiment, the signal generated by thepressure sensor 14 is stored in a database 18 communicably coupled tothe controller 16. In other embodiments, the signal generated by thepressure sensor 14 is stored in an internal memory (not shown) of thecontroller 16. In one embodiment, the controller 16 is a part of onboardanalytics system (not shown) and adapted to analyze the signals receivedfrom the pressure sensor 14. Alternatively, the controller 16 may becommunicably coupled to the onboard analytics system.

The controller 16 is configured to retrieve the signal indicative of thepressure generated by the fracking pump 12 over a predefined period oftime from the database 18 or the internal memory of the controller 16based on application requirements. In an exemplary embodiment, thecontroller 16 may retrieve pressure signals data of four hours forfurther processing. The controller 16 is configured to analyze thesignal and identify one or more work cycles of the fracking pump 12within the predefined period of time.

In one embodiment, the controller 16 may include a low pass filter 20for processing the signal prior to identifying the work cycles of thefracking pump 12. The low pass filter 20 is adapted to filter out highfrequency components in the signal received from the pressure sensor 14.Accordingly, the controller 16 generates the filtered signal indicativeof the pressure generated by the fracking pump 12 over the predefinedperiod of time. In another embodiment, the controller 16 may performbacklash filtering in order to filter out minor variations in the signalprior to identifying the work cycles of the fracking pump 12 based onapplication requirements.

The controller 16 analyzes the signal to determine one or morecharacteristics of each of the identified work cycles. The signalcharacteristics include the peak pressure, the average pressure, thetime duration, and the like. The controller 16 is configured todetermine a type of the work cycle of the fracking pump 12 based on theone or more characteristics. In other words, the controller 16identifies that the fracking pump 12 is operating in one of the systemtest cycle, the fracking cycle, and the perforation cycle. A personskilled in the art will appreciate that various other signalcharacteristics may be used to aid in the identification of the type ofthe work cycle.

FIG. 2 illustrates a graph 22 of the pressure generated by the frackingpump 12 with respect to time according to an example embodiment of theinvention. The graph 22 shows a pressure profile 24 which refers todischarge pressure values corresponding to the signals received from thepressure sensor 14 plotted against time. Moreover, the graph 22 showsthe pressure profile 24 after the signals is filtered through the lowpass filter 20. Data corresponding to the pressure profile 24 may bestored in the database 18. In the illustrated embodiment, the pressureprofile 24 shown in the graph 22 is for the time interval of 40,000seconds and the time interval may vary based on applicationrequirements.

The graph 22 shows different types of work cycles of the fracking pump12 namely, the system test cycle, the fracking cycle and the perforationcycle. During the system test cycle, the fracking pump 12 is subjectedto system test involving very high pressures to identify any potentialfailure such as leakage. Further, the system test cycle has very shorttime duration, for example, 10 minutes. The system test may be performedby the site operator after every fracking and perforation operation oras per the application requirements. During the fracking cycle, thefracking pump 12 discharges fluid at high pressure to the rock formationhaving trapped oil and/or gas. This result in fracturing of the rockformation leading to increased fluid flow and drop in discharge pressureof the fracking pump 12. During the fracking cycle, the rock formationmay be fractured multiple times resulting in one or more small pressurehumps in the pressure profile 24. Typically, the fracking cycle has timeduration more than the system test cycle and the perforation cycle.

During the perforation cycle, a perforation gun (not shown) is lowereddown the drill pipe. Once the perforation gun reaches the requiredposition, the perforation gun is fired to expose the rocks to thefracking fluid. One or more large pressure humps are typically seenduring the perforation cycle. Further, the time duration of theperforation cycle is greater than the time duration of system test cyclebut less than the time duration of the fracking cycle.

The controller 16 is configured to identify a boundary (also referred as“cycle boundary”) of a work cycle of the fracking pump 12 within thepredefined period of time. In one embodiment, the controller 16determines one or more cycle boundaries from the analysis of thepressure profile 24. A cycle boundary corresponding to a work cycle maybe identified from a slope of the graph 22. Each cycle boundarycorresponds to either a cycle start or a cycle end corresponding to thework cycle. Further, the cycle boundaries are associated with a highvalue of positive slope or a low value of negative slope in the graph22. The controller 16 may determine one or more cycle boundaries basedon whether the slope of the graph 22 is greater than a positive slopethreshold or lesser than a negative slope threshold.

For example, in the illustrated embodiment, the controller 16 determinesa first cycle boundary “B1” indicating a start of a first work cycle. Atthe first cycle boundary “B1”, the graph 22 has a first slope thatexceeds the positive slope threshold. In the illustrated embodiment, thepositive slope threshold is 10, and may vat based on applicationrequirements. Further, the controller 16 determines a second cycleboundary “B2” indicating an end of the first work cycle. At the secondcycle boundary “B2”, the graph 22 has a second slope that is less thanthe negative slope threshold. In the illustrated embodiment, thenegative slope threshold is negative (−) 5. Similarly, the controller 16determines a third cycle boundary “B3” indicating a start of a secondwork cycle.

At the third cycle boundary “B3”, the graph 22 has a third slope thatthat exceeds the positive slope threshold. Further, the controller 16determines a fourth cycle boundary “B4” indicating an end of the secondwork cycle. At the fourth cycle boundary “B4”, the graph 22 has a fourthslope that is less than the negative slope threshold, In a similarmanner, the controller 16 determines a fifth cycle boundary “B5”indicating a start of a third work cycle and a sixth cycle boundary “B6”indicating an end of the third work cycle. The first work cycle, thesecond work cycle, and the third work cycle are denoted in the graph 22as “W1”, “W2”, and “W3” respectively. A person skilled in the art willappreciate that use of slope data for identifying the cycle boundariesis merely for illustrative purposes and one can employ any otherparameter apart from the slope data to identify the cycle boundaries.The slope threshold may be stored in the database 18 or the internalmemory of the controller 16 and may be retrieved by the controller 16 byany known data retrieving method.

It should be noted that in other embodiments, the graph 22 may includemultiple cycle boundaries without any limitation. Also, the controller16 may be configured with a plurality of positive and negative slopethresholds for different cycle boundaries based on applicationrequirements. In other embodiments, based on the number of cycleboundaries, the controller 16 may determine a single or multiple workcycles in the graph 22 without any limitation, Using the cycleboundaries, the controller 16 is configured to determine duration ofeach work cycle identified from the analysis of the data.

The controller 16 is configured to determine one or more characteristicsof the signal using the pressure profile 24. In one embodiment, thecontroller 16 determines the peak pressure of each work cycle. Forexample, the peak pressure in the first work cycle “W1” is denoted by“PP1” in FIG. 2 corresponding to 64000 Pressure per Square Inch (PSI).Similarly, the controller 16 determines the peak pressure of the secondwork cycle “W2” and the third work cycle “W3” denoted by “PP2” and “PP3”respectively. The controller 16 is further configured to compare thepeak pressure with one or more peak pressure thresholds. The controller16 may be configured with different peak pressure thresholds fordifferent work cycles. For example, a peak pressure threshold for thesystem test cycle is 60000 PSI, a peak pressure threshold for thefracking cycle is 40000 PSI, and a peak pressure threshold for theperforation cycle is 25000 PSI. The peak pressure thresholds may bestored in the database 18 or the internal memory of the controller 16and may be retrieved by the controller 16 by any known data retrievingmethod. Using these peak pressure thresholds, the controller 16identifies the type of the work cycle for each of the work cycles.

In one embodiment, the controller 16 is configured to use the timeduration of the work cycle to determine the type of the work cycle. Thecontroller 16 may be provided with time ranges for each type of the workcycle. For example, the system test cycle has very small duration ofaround 30 minutes. Thus, the controller 16 determines the first workcycle “W1” as the system test cycle. In a similar manner, the controller16 determines the second work cycle “W2” as the fracking cycle and thethird work cycle “W3” as the perforation cycle. The time ranges for eachtype of the work cycle may be stored in the database 18 or the internalmemory of the controller 16 and may be retrieved by the controller 16 byany known data retrieving method.

The controller 16 may be configured to use various other characteristicsof the signal to aid in determination of the type of the work cycle. Inone embodiment, the controller 16 determines a number of small humps inthe pressure profile 24 within each work cycle. Small hump is defined asa hump having magnitude of more than 400 PSI and less than 10,000 PSI inan example embodiment. Referring to FIG. 2, the controller 16 determinesthat there are 4 small humps during the second work cycle “W2”. Inanother embodiment, the controller 16 determines a number of large humpsin the pressure profile 24 within each work cycle. Large hump is definedas a hump having magnitude of more than 10,000 PSI. Referring to FIG. 2,the controller 16 determines that there is one large hump in the thirdwork cycle “W3”. Using the count of small humps and large humps, thecontroller 16 may determine the type of the work cycle. For example, ifthere are more than 3 small humps in the work cycle, the controller 16determines that the work cycle is the fracking cycle.

In various embodiments, the controller 16 uses various machine learningalgorithms to determine the type of the work cycle. In machine learningalgorithms, a labeled data set is prepared for training and testing thealgorithm. Data corresponding to at least one of the signalcharacteristics such as peak pressure, time duration of work cycle,number of small humps, and number of large humps may be included in thelabeled data set. As an example, 70% of the labeled data set is used fortraining the algorithm and 30% of the labeled data set is used fortesting the algorithm. The controller 16 further identifies one or moresignal characteristics which are suitable for machine learning.Techniques such as box plot and scatter plot may be used to identifysuitable parameters for machine learning.

In one embodiment, Linear Discriminant Analysis (LDA) algorithm is usedfor determining the type of the work cycle. In another embodiment,Ensemble Subspace Discriminant Analysis algorithm is used fordetermining the type of the work cycle. A person skilled in the art willappreciate that Linear Discriminant Analysis algorithm and EnsembleSubspace Discriminant Analysis algorithm are mentioned merely forillustration purposes and various other machine learning algorithms maybe used by the controller 16. For example, algorithms such as SupportVector Machines, k Nearest Neighbors, Random Forest, Bagged and BoostedTrees may be used as machine learning algorithm by the controller 16.Confusion matrix and True Positives graph may be plotted for theaforementioned machine learning algorithms to evaluate the performanceof the algorithms.

It should be noted that a sequence of the system test cycle, thefracking cycle, and the perforation cycle described herein is merelyexemplary and may vary based on application requirements. For example,in other embodiments, each of the first work cycle “W1”, the second workcycle “W2”, and the third work cycle “W3” may be any of the system testcycle, the fracking cycle, and the perforation cycle in any order basedon application requirements.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a method 26 of working of the workcycle determination system 10 for determining the work cycle of thefracking pump 12. Referring to FIG. 3, a flowchart of the method 26 isillustrated. At step 28, the controller 16 receives the signalindicative of the pressure generated by the fracking pump 12 from thepressure sensor 14. The controller 16 receives the signal over thepredefined period of time. Additionally, the low pass filter 20 providesfiltering of the high frequency components from the signal. In someembodiments, backlash filtering may be performed in order to filter outminor variations in the signal.

At step 30, the controller 16 identifies a boundary of a work cycle fromthe analysis of the signal. In one embodiment, the controller 16determines the first cycle boundary “B1”, the second cycle boundary“B2”, and so on based on the slope thresholds. At step 32, thecontroller 16 determines the peak pressure of the work cycle. Thecontroller 16 compares the peak pressure of the work cycle with one ormore peak pressure thresholds. The controller 16 may be configured withvarious peak pressure thresholds corresponding to different types of thework cycles.

At step 34, the controller 16 determines the time duration of the workcycle. The controller 16 may be configured with various time rangescorresponding to different types of the work cycles. At step 36, thecontroller 16 determines the type of the work cycle of the fracking pump12 based on the peak pressure and the time duration of the work cycle.The work cycle may be one of the system test cycle, the perforationcycle, and the fracking cycle.

The work cycle determination system 10 provides a simple, efficient, andcost effective method 26 of determining the type of the work cycle ofthe fracking pump 12. The determination of the work cycle may he furtherused for additional operational analysis of the fracking pump 12 such asperformance evaluation, determining service schedule, componentreplacement schedule, pump utilization, and so on. The work cycledetermination system 10 may be incorporated in any system with little orno modification to the existing system.

While aspects of the present disclosure have been particularly shown anddescribed with reference to the embodiments above, it will be understoodby those skilled in the aft that various additional embodiments may becontemplated by the modification of the disclosed machines, systems andmethods without departing from the spirit and scope of the disclosure.Such embodiments should be understood to fall within the scope of thepresent disclosure as determined based upon the claims and anyequivalents thereof.

What is claimed is:
 1. A work cycle determination system for a frackingpump, the work cycle determination system comprising: a pressure sensorassociated with the fracking pump, the pressure sensor adapted togenerate a signal indicative of a pressure generated by the frackingpump; and a controller communicably coupled to the pressure sensor, thecontroller configured to: receive the signal indicative of the pressuregenerated by the fracking pump over a predefined period of time;identify a boundary of a work cycle within the predefined period of timeby analyzing the signal; determine a peak pressure of the work cycle;determine a time duration of the work cycle; determine a type of thework cycle of the fracking pump based on the peak pressure and the timeduration of the work cycle.
 2. The system of claim 1, wherein the typeof the work cycle is at least one of a system test cycle, a perforationcycle, and a fracking cycle.
 3. The system of claim 1, wherein thecontroller is configured to filter the signal received from the pressuresensor through a low pass filter.